Creating orthogonal axis in blender (geometric model)
I would create a Cube and position then delete unwanted Edges in Edit mode.

In Object Mode I would press Alt+C to convert the Object to a Curve from Mesh and then in the Data Tab for Curve, Fill: Full at a Depth and Resolution that suits my needs.

Once settled, I could color the axis or texture the object by converting it BACK to a Mesh from Curve so I was back on familiar ground (Curves have different behaviors).